Method of removing vesicant particles



Patented Feb. 6, 1951 UNITED STATES ATENT OFFICE METHOD OF REMOVING VESICANT PARTICLES No Drawing. Application April 17, 1931, Serial No. 531,000

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 4 Claims.

This invention described herein may be manufactured and used by or for the Government for government purposes, without the payment to me of any royalty thereon.

This invention relates in general to protective clothing and more particularly has reference to a process of treating material for rendering it resistant to vesicant gases and vapors, and to the product resulting from the treatment.

Previous to this time, it has been attempted to fix chlorine on material for protecting against such gases as mustard, but the impregnated cloth has increased in weight and has been characterized by stickiness. Also, the permeability of the same has been lowered to such an extent as to make'clothing made of material so treated, uncomfortable to the wearer.

' ,A..primary object of this invention is to provide material relatively impermeable to vesicant 'gasesor vapors.

Another object of this invention is to provide material having semi-permeable properties, that is; material which is permeable to air and inert gases, but impermeable to mustard gases and similar substances.

Another object of this invention is to devise a process for producing material having properties rendering the same impermeable to mustard gases and substances having similar properties.

Yet another object of this invention is to provide a process for fixing chlorine on textile material without appreciably afiecting the desirable permeable characteristics thereof.

A further object of this invention is to provide a process for chlorinating material to render the same impervious to mustard gas and similar substances without materially increasing the weight of the material.

Still another object of this invention is to devise a process of treating clothing to render the same impervious to vesicant and toxic gases or vapors, such as mustard gas, Lewisite and similar substances.

A still further object of this invention is to devise a process for fixing chlorine in material to render the same impervious to mustard gas and similar substances without appreciably changing the desirable physical characteristics thereof.

. With these and other objects in view which 5 may be incident to my improvements, the invention consists in the method to be herein set forth and claimed, with the understanding that the several necessary steps comprising the invention may be accomplished in any order found most suitable for carrying the same into practi-- cal efiect, without departing from the spirit of the invention and the scope of the appended claims.

The present invention comprehends directly fixing chlorine by a chemical combination on material having the characteristics of wool so as to render the same impervious to mustard gas and similar vesicant and toxic gases. One manner of practically efiecting the concept of the invention is to subject wool or similar materials, to a chlorinating process involving the use of a mixture of a stable hypochlorite and a suitable alcohol. The invention also comprehends incorporating the chlorinating agents, mentioned above, in an inert solvent. By the process forming the subject matter of the invention, wool having its normal water content under usual atmospheric conditions may be chlorinated or it may first be dried before subjecting it to chlorination. In either instance, the Wool is washed with a solution of an inert solvent subsequent to chlorination and may also be dechlorinated and washed again.

Wool is considered to be composed of a protein substance, known as keratin. It has been found that when wool is subjected to the action of chlorine, that a reaction takes place between the chlorine and the wool which, it is thought, produces chloramines. However, it has been found that in some instances no chloramines have been formed. Regardless of the theory of the reaction which takes place between the wool and the chlorinating agent, there is a change effected in the characteristics of the wool which is desirable for certain purposes, among which is that of rendering mustard gas and similar substances non-vesicant.

In permeable protective clothing, it is desired to incorporate therein as high a percentage of active chlorine as can be introduced into wool without damage of the cloth. Wool which contains 4 per cent to 7 per cent of active chlorine is practical for use as protective clothing. The active chlorine, as considered here, is determined 0 by titration of the iodine liberated by a known 3 weight of the chlorinated wool from the acidified solution of potassium iodide and is calculated on the basis of one chlorine atom being the equivalent of two atoms of iodine. Processes employed 4 quires but a relatively small amount of time for completion. Moreover, it is to be noted that only small amounts of the hypochlorite are required and the most of it is actually utilized in in the past for the introduction of more than 5 the chlorination reaction. With the use of an 4 per cent of active chlorine into wool by means inert solvent, such as carbon tetrachloride, a of chlorinating agents in aqueous medium, such large volume of chlorinating bath may be obas hypochlorous acid, cause considerable damage tained with a small amount of hypochlorite. to the wool, rendering it substantially useless. During chlorination, the presence of water In practicing the process to be hereinafter degreatly damages the wool and for this reason it scribed, I am able to introduce either small or is preferred to use anhydrous hypochlorites and large percentages of chlorine into wool to suit alcohols. the requirements for which the cloth is intended The actual chlorinating agent in the reaction without causing damage thereto and so controlof tertiary butyl hypochlorite and absolute ling the process that the same is attended :by methyl alcohol with 'wool is of an entirely difuniform results. ferent character from that which operates in the I have found that a mixture of an organic -Jchlorina'tion of wool with tertiary butyl hypohypochlorite possessing suitable stability and chlorite alone. When anhydrous tertiary butyl certain alcohols affords an efficient 'chlorinating hypochlorite is mixed with absolute methyl alagent for permanently fixing any desired percohol, a violent reaction has been found to occentage of chlorine on wool without causing our after a short time interval, and the rate of damage thereto. Particularly adapted V to this the chlorination reaction involving a mixture of purpose are tertiary butyl hypoch'loriteand abtertiary butyl hypbchlorite and absolute methyl solute methyl alcohol. 'In order to obtain a betalcohol proceeds much more rapidly than with ter control with the reactiveagents, I have found the use of tertiary butyl hypochlorite alone. it preferable to incorporate the same in an inert While I do not wish to "limit myself to-any exsolvent such as carbon tetrachloride. planati'on of the reaction which occurs when While I have employed carbon tetrachloride methyl alcohol is mixed with tertiary butyl hywith marked success and although I deem it prefpochlorite, I believe that the actual chlorinaterable to employ a "mixture of tertiary butyl hying agent is methyl hypochlorite, which is bepochlorite and absolute methyl alcohol in solulieved "to be formed according to the following tion with an ine'rt's'dlvent'such as carbon tetraequation: chloride, any other suitable organic hypochlov rite having suitable stability 'such as tertiary (CH2)3CO'C1+CH3OH- CH3):iCO-H+CH3OC1 amyl hyp'o'chlori'te may be used and also any pri- V V p l t mary or secondary alcohol containing from one In 'Slmllar ethyl hypgchlonteJn the to carbon atdfns such as absolute ethyl-a1- nascent state is probably the actual chlorinating 601,101, also propyl, m secondary butyl agent in the reaction of tertiary .bu'tylshypochloand primary and secondary amyl alcohols. The 3 'jetthyl alcohol use of ingredients "other than those preferred, 40 q q e xamples,:as .given n the table however, have been "found less satisfactory as will more Iully illustrate theiinvention, but -1t:.is the pronounced instability of-other mixtures and to be distinctly understoodthat 'theyfare ot i fih limited mo t c e which can be tended to constitute any limitations in'the scope "troduc'ed into the wool b'y'the 'useof the same thereoflessen t utility of these m In the following tables particular attention In practicing my invention, I have treated vShould be given to the ff ts pr duc d upon wool containing the normal water content of the the p rcentages ofchIQrine nXed onthe Wo'Ol by same under usual atmospheric "conditions and the v nt conderitratidn'of th hyp a i d 1 wit t 'u of 1 comaim chlorites and alcohols disclosed, as well as their ing the or l Water tent u de u al t- 59 volumes and that of the, inert solvent. Also to mos pheric d t d t p r e ta gt be noted are the variations in temperatures and hlo i p t f u a v' te t p r ent by the "time for which the wool is subjected to the weight of the wool may be introduced into the chlorinating bath. Moreover, the initial consame without damage. In 'chlor'inating wool dition of the wool p'rior'to-chlorination and 'it's Which has been dried, h e e h as o er effect upon the final results noted should be phosphorus pentoxide or other efiicient desic- COnSidered. eating agents, or by heating in a stream of dried The data tabulated in the first'table was obair at about C., as high'as six to seven'per cent tained from experiments conductedinthe 0mmof active chlorine may be introduced into the nation of Woole ti ofh'which had been dried wool without affecting the quality thereof. 60 in a vacuum desiccator-"over phosphorus pent- As will hereinafter appear, chlorination of oxide for forty 'eight hours. In regard to the wool by means of a stable hypochlorite and an tearing strength or "the chlorinated cloth, itwas alcohol incorporated in an inert solvent, may found that it was substantially the 'same'as that be easily controlled, while obtaining uniform reof the original cloth for each 'experimen'tcarsults, and at the same time the chlorination re- 5 ried out. 7 i

{Fable 1 v Tertiary Bu-tyl Moth 1A1 '11 1' Carbon- I i.

Hypochlorite y 00 I W001 Perqent cififfii'e; 11th? t?" Usedv ctitr-ifie 00., Per Cent 00. Per Cent g' Cloth 25 251 ii? 28 322 ii? it i8 iii 02:2 25 15.1 20 12.1 H U 2o y) .-;32 -34 15 I 5. 0

5. l't has been mentioned that the process of the 'present invention may be applied to the chlorination of undried woolen cloth. However, the chlorination of undried woolen cloth to fix. percentages of active chlorine on the wool higher than 4 per cent to 4.5 per cent causes damage to the cloth. Table 2 illustrates the results obtained in'the chlorination of woolen cloth containing its normal water content under the prevailing atmospheric conditions. To be noted is the fact that the wool was undamaged in experiments in which 1.2 per cent, 3.3 per cent and 3.8 per cent of active chloride was introduced into the cloth, while the experiments introducing 5.3 per cent and 6.5 per cent of active chlorine into the wool damaged the cloth.

content under usual atmospheric conditions is chlorinated to fix percentages of active chlorine on the wool of a higher range than from 4 to 4.5 per cent, the wool is slightly damaged as pointed out in the consideration of Table 2.

W001 may also be chlorinated by means of a mixture of tertiary butyl hypochlorite and absolute methyl alcohol without the use of carbon tetrachloride or other diluents. Under these conditions, the reaction proceeds at such a rapid rate that proper control of the reaction is difficult. This may be readily observed from an inspection of Table 3, wherein wool containing its normal water content under prevailing atmospheric conditions is chlorinated by the use of tertiary butyl hypochlorite and methyl alco- In the foregoing tables it should be noted that the time of the reaction may be varied to reguhol without employing a diluent such as carbon tetrachloride.

Table 3 TertiaryButyl P C t Hypochlorite Methyl Wool er Condition of Alcohol, g 33 Use e Chlooll inzlilted cc. g. ot cc. Per Cent m Cloth 10 9.0 100 15 23-24 2 l. 7 Undamaged. 2] 17. 3 100 15 22-23 2 1. 9 Do. 34 28. 8 84 22 21-22 2 5. 4 Slightly damaged. 50 45. 4 60 15 23-26 2 5. 4 D0. 50 45. 4 60 60 4-7 3 4. 6 Undamaged. 78 71. 5 31 15 23-25 2 3. 0 D0.

late the amount of chlorine which it is desired to introduce into the wool. The amount of active chlorine introduced into the wool may also be controlled by varying the relative amounts of tertiary butyl hypochlorite, methyl alcohol and carbon tetrachloride and regulating the time the reaction is allowed to proceed. In addition to this, the time of the reaction may be greatly reduced by additionally increasing the concentrations of the reactive constituents, and also by decreasing the quantity of solvent and raising the temperature at which the reaction is carried out. It will be manifest, however, that the reaction must be controlled within certain limits, for if wool containing the normal water factory than chlorination with tertiary butyl hypochlorite and absolute methyl alcohol.

In the following Table 4, illustration of the results obtained in the chlorination of woolen cloth, containing its normal water content under prevailing atmospheric conditions, with tertiary butyl hypochlorite and absolute ethyl alcohol in carbon tetrachloride are given.

While I, as previously stated, prefer to carry on my chlorinatihg process within a mixture of tertiary butyl hypochlorite and absolute methyl alcohol, I may substitute other organichyp'ochlorites having suitable stability, i 'place of the/tertiary butyl hypoehlorite. For example, 'woolmay be chlorinated for use as protective clothing by means of a mixture or tertiary 'amyl .hypochlorite and methyl "alcohol.

Having described the process in general; and given tabulated results obtained from carrying out the same, one specific example will be given to more fully illustrate the invention, although it is to be understood that the invention is not to be limited by the proportions of the reactants given therein or of the treatment, as it-is obvious that the method may be varied, as previously out chloride. To carry out the chlorination reaction, I

a 750 cc. Erlenmeyer flask, which is provided with a rubber stopper having two openings therein, is employed. In one of the openings there is inserted a thermometer which is in contact and partially immersed inthe reaction solution. The other opening is provided with an outlet tube attached to a calcium chloride drying tower. Throughout the reaction the flask is kept closed. By Warming the chlorinating solution in a bath of water, its temperature is raised to 32 C. Within five minutes after mixing the constituents of the solution, about g. of dried wool is quickly transferred from the desiccator to the chlorinating bath. Due to the heat of the reaction, the temperature of the bath soon begins to rise and slight cooling becomes necessary. The solution is frequently shaken or mechanically stirred and its temperature is kept-at 32 C. to 34 C. throughout the reaction.

This treatment of the cloth is continued -from forty to forty-five minutes after which the solution is quickly decanted, and the wool, while still in the flask is washed with carbon tetrachloride. After the washing, just described, the wool is quickly removed from the flask and again washed in three baths of carbon tetrachloride. It will be found that cloth treated in this manner contains from 6 per cent to 7 percent of active chlorine based on the weight of the wool.

If desired, the cloth may be 'washed with water after thoroughly washing with carbon tetrachloride. By varying the time of the chlorination reaction, the active chlorine on the wool can be brought to the amount desired. In a typical experiment, the amount of active chlorine fixed on the wool in forty-five minutes was 6;? per cent.

[It will be apparent from the foregoing descriptionthat the presence of small amounts :of. water in the chlorinating reagents is ot detrimental to any 'appreciable:-extent. As water .has a tenden'cy to "damage Wool and in any substantial quantity does cause damage with increasing amounts, it is preferred, as previously indicated, to employ an-hydrous reagents.

From the foregoing description it will be appreciated thatan improved process for the chlorinationof wool to render the same impervious to -mustard; gas and the like, without causing .d-amage to the wool, has been provided byt reating the wool with a mixture of suitable alcohols and organic hypochlorites possessing the frequired stability. Bythe use'of carbon tetrachloride as a solvent for the alcohol and the hypochlorite an easily controllable process of chlorination is aiforded. Itshould also be noted that with the ease of 'c'o'iitrol, by the variation of the concentration of the chlorinating solution, the time of the reaction, and the temperature at which it is carried out, the amount of active chlorine fixed to the woolen cloth may be varied to meet the particular requirements called for.

In the foregoing description and accompanying claims the terms ve'sicants, or vesicant gases or vapors are intended to include gases, vapors or liquids. The term mustard gas designates the vesicant compound bis (beta-chlorethyl) sulphide which may be in the gaseous, vapor or liquid stage.

Although -I have described the preferred em- 'bodim'ent of my invention, .I'. wish -it 'to be understood that I. do not confine myself to the precise details herein set forth by Way of illustration, as it is apparent that many changes and variations may be made therein by those skilled in the art, without departing from the spirit of the invention or exceeding the scope of the appended claims.

I claim:

1. A method of removing vesicant particles 1 from vesicant contaminated air which comprises ;passing the air through woolen material which has been treated with a tertiary alkyl hypo- REFERENCES siren The following references file of this patent: V I

UNITED STATES PATENTS Number 1,522,555 2,132,342

are of record in the Name Date Trotman Jan. 13, 1925 Jackson Oct. 4, 1938 

1. A METHOD OF REMOVING VESICANT PARTICLES FROM VESICANT CONTAMINATED AIR WHICH COMPRISES PASSING THE AIR THROUGH WOOLEN MATERIAL WHICH HAS BEEN TREATED WITH A TERTIARY ALKYL HYPOCHLORITE AND AN ABSOLUTE ALCOHOL FROM THE GROUP CONSISTING OF METHYL ALCOHOL AND ETHYL ALCOHOL INCORPORATED IN AN INERT SOLVENT. 